Alex Lopex (suicide silence) kick drum set up

[Malvore]

So, I've seen suicide silence play a few times before live as well as videos of them. And every time, I notice the drummer has two kick drums set up but only mic's one of them. Therefore he must be using double kick with the other drum just sitting there.

Just wondering if anyone else has noticed this and/or has an explanation why anyone in their right mind would do this, espeicially on tour haha. : P